Resonator for phonographic reproducers.



c. HARTMANN. RESONATOR FOR PHONOGBAPIIIO RBPRODUOERS. APPLICATION FILEDMAR. 13, 1908.

907,794. 7 V Patented Dec. 29, 1908.

Z I gvwewfoz 3514 QHO'LMM IIll/IIII/I/II/I/zh.

PATENT OFFICE,

CARL HARTMANN, or NEWYQRK, N. Y.

RESONATOR FOR PHONOGRAPHIG REPRODUCERS.

To all whom it may concern:

Be it known thatI, CARL HARTMANN, a citizen of the United States ofAmerica, residing at New York, in the borough of the Bronx, county andState of New York, have invented certain new and useful Improvements inResonators for Phonographic Reproducers, of which the following is aspeciiication.

0 This invention relates to an improvement in phonographic reproducersby which the sounds reproduced by, the same are rendered clearer andmore distinct than heretofore; and the invention consists in adding tothe ordinary reproducer-box containing the diaphragm an extension orresonator which is closed at the outer end and provided at its inner endwith an auxiliary d aphragm, the frame of which is tightly fitted intothe inner end of the resonator, and which serves for increasing thesounds reproduced by the main or reproducing diaphragm.

In the accompanying drawings, Figure 1 represents a perspective view ofa phonograph with my improved reproducer, Fig. 2 is a perspective Viewof the reproducer, drawn on a larger scale, and 1 ig. 3is a verticallongitudinal section on line 3, 3, Fig.2.

Similar letters of reference indicate corresponding parts.

Referring to the drawings, a represents the box, I) the diaphragm and cthe style of a phonographic reproduc-er of the usual approvedconstruction. The style is operated either by a record-disk, cylinder orother record-tablet. The reproducer-box a is connected by asound-conducting tube 01 with the horn h in the usual manner. The boxois provided in its rear-wall with an opening 0 for establishingatmospheric pressure at the interior of the reproducer-box a. a To theupper part of the rear-wall of the box a is applied a resonator-box ewhich is closed at its outer end and attached by its open inner end tothe rear-wall of the box a, the-resonator surrounding an opening 0 inthe rear-wall of the reproducer-box. The resonator-box 2 may be made insemicircular or of other cross-section, and preferably of taperingshape, being widest at its point of connection with the rear-wall of thereproduc'er-box a.

The inner end of the resonator-box q is closed by an auxiliary diaphragmf of mica,

which is supported in a supporting frame Specification of LettersPatent. Application filed. March 13, 1908. Serial No. 420,930.

Patented Dec. '29, 1908.

having a flange f, which latter is inserted into the inner end of theresonator e, the rim of the frame' overlapping the opening 0 in therear-wall of the box a, while the flange f 2 fits tightly into the innerend of the resonator-box e. The auxiliary diaphragm f serves for thepurpose of throwing the sounds produced by the reproducing diaphragm inforward direction through the sound-conducting tube to the horn and ofincreasing thereby the sounds to a considerable extent so as to producea clearer and louder reproduction of the same. This is caused by thefact that as the auxiliary diaphragm is located at the rear of themaindiaphragni with respect to the horn, it acts (in connection with theresonator-box e) in the nature of a sounding-board by which thesound-waves are reflected toward the horn. The vibrations of thereproducing diaphragm are transmitted to the auxiliary diaphragm andvthe sound is reflected therefrom in i11- creased volume due to theaction of the resonator-box. The air in the resonator-box serves as acushion for the auxiliary diaphragm, so that the same follows thesoundvibrations set up in the reproducing diaphragm.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. In a phonographic reproducer, the combination, with the reproducingbox, diaphragm and style of the same,said box being provided with anopening in its rear-wall, of

a resonator-box extending from said opening and closed at its outer end,and an auxiliary diaphragm located at'the inner end of saidresonator-box;

2. In a phonographic reproducer, the combination, with a diaphragm andinclosing reproducer-box, of a resonator-box closed at the outer end andextending outwardly from an opening in the wall of the reproducer-box,and an auxiliary diaphragm inserted into the opening of thereproducer-box and closing the inner end of the resonator-box.

3. In a phonographic reproducer, the com bination, with areproducer-box,diaphragm and reproducing style, of a resonator-box of tapering sha eextending outwardly from an opening in t e wall of the reproducer-box,said resonator-box being closed at the outer end and open at the innerend, and an auxiliery diaphragm the frame of which is 10- diaphragm thatis tightly fitted by its frame cated in the opening of thereproducer-box into the larger opening of the reproducer-box and innerend of the resonator-box. and inner end of th'e resonator-box.

4. In a phonographic reproducer, the com- I bination, Withthe-,.,reproducer-box, diamy invention, I have signed my name in phragmand style, said box being provided l presence of two subscribingwitnesses.

{with an air opening in the lower part and a CARL HARTMANN arger opening1n the upper part of its well, of a resonator-box closed at the outerand l open at the inner end and extending out- E wardly from saidopening, and an auxiliary l Witnesses PAUL GoEPEL, ANTON KoPKA.

In testimony, that I claim the foregoing as .p

